Apparatus for producing titanium metal



May 14, 1957 E. J. DUNN APPARATUS FOR PRODUCING TITANIUM METAL Filed April 23, 1954 M mu nu mm IN VEN TOR.

Eon/14AM J. au/v/v A TTORNE Y5 APPARATUS FGR PRODUCING TITANIUM NlETAL Edward J. Dunn, Newton Center, Mass. Application April 23, 1954, Serial No. 425,341

4 Claims. (Cl. 1331) (Granted under Title 35, U. S; Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates to the production of titanium metal and appertains to an improved apparatus and method of the type disclosed in the pending United States patent application, Serial No. 329,939 of Manual Goldman and Arthur F. I ones, filed on January 6, 1953, now abandoned. Titanium metal due to its advantageous characteristics has many useful purposes at present and could potentially serve many more due to its desirable characteristics of lightness, strength, corrosion resistance, low coefficient of expansion, and surface hardening properties. This metal possesses advantages over the combined characteristics of steel and aluminum without the disadvan tages of density of the former and the relatively low strength and low-corrosion resistance of the latter.

The utilization of titanium on a larger scale commercially is hindered to a large extent only by the lack of more economical and more productive methods. This hindrance is due mainly to the ready contamination of titanium by oxygen, nitrogen, carbon and other atmospheric reacting elements with which the titanium comes in contact during refining of this metal. Accordingly, it is an object of this invention to provide a method and apparatus for producing substantially pure titanium metal in an atmosphere substantially free of contaminating gases and in a manner more economical and more expeditious than by heretofore known methods and in quantities sufiicient for large scale commercial use. The method and apparatus of the invention is adapted to the production of titanium by both the batch and continuous method.

It is another object of this invention to provide a method of producing metallic titanium by the thermal decomposition of a volatized titanium halide without the disadvantage of having the metal adhere to or deposit on the furnace wall with the subsequent necessity of cutting or stripping the metal from the wall.

A more particular object of this invention is to provide means for cooling the wall of an inductively heated dissociating furnace to a temperature below that at which thermal decomposition of titanium tetraiodide occurs while inductively heating the metal particles within the furnace to the decomposition temperature of the halide and thereby provide a surface at a proper temperature on the particles upon which titanium metal will deposit. This furnace may be operated at a reduced pressure or at a slight positive pressure.

A further object of this invention is to provide a plurality of dissociating furnaces arranged in parallel to permit the evacuation of the deposited titanium from each of the furnaces during the batch method without interrupting the continuous production 'of metal in the Other furnaces.

A still further object of this invention resides in the provision of an inclined dissociating furnace so con- 2,792,438 Patented May 14, 1957 structed as to permit the continuous production of titanium metal by thermal decomposition and removal of the metal without interruption in operation of the furnace.

Other objects and advantages of the invention will be apparent during the course of the following description.

The invention will be more fully described in the following description taken in connection with the accompanying drawing forming a part hereof and in which:

Fig. 1 illustrates, in a conventional and diagrammatic manner, an apparatus embodying the invention, showing one of the vacuum dissociating furnaces in detail in verti cal section.

Fig. 2 is a sectional view of a portion of a modified form of the invention showing an arrangement of an inclined rotary dissociating furnace.

In the apparatus according to this invention, after the evacuation of air or other gases which may be present in the dissociating furnace, titanium halide, preferably titanium tetraiodide, is admitted into the furnace. The titanium halide for use in the dissociating furnace may be produced by any of various well known methods, as for example in obtaining titanium tetraiodide a charge of crude titanium, such as ilmenite or rutile, preferably in powdered form, is placed into a hopper, pure iodine in the solid state added thereto, and the charge is subjected to heat. The various titanium iodides resulting from this reaction are then fractionated to withdraw the vaporous tetraiodide which is used in the dissociating furnace.

In the dissociating furnace, upon the thermal decomposition of the titanium halide to titanium metal, the free metal accumulates on the surface of particles of titanium, tungsten or other suitable material which has been introduced into the furnace for this purpose. The titanium metal deposited on such particles is removed periodically from the furnace. The halide gas liberated by the decomposition is withdrawn from the furnace and is condensed and recirculated for reuse by conventional apparatus.

The decomposition of the tetraiodide, according to the invention, may be carried out in a single furnace, or in a plurality of furnaces supplied with titanium halide from a common source and arranged in parallel relation and so that the individual furnaces may be selectively disconnected and unloaded without interfering with the operation of the remaining furnaces.

An inclined furnace having a substantially greater length to provide a considerably longer deposition period for the metal, may be used; and an atmosphere sealing valve arrangement provided at the outlet, permits the continuous refining and removal of titanium from the apparatus without the ingress of contaminating elements into the system. p

In the apparatus shown in Fig. 1, described in connection with the production of titanium metal from titanium tetraiodide, air and other contaminating gases are removed from the system by means of a conventional arrangement of vacuum pump 2 and condensation pump 4, and a charge 6 of powdered titanium ore and iodine in solid form is received into the closed reactor 8. by

means of the inlet 10. A conventional heating arrangement, such as the gas burners 11, may be utilized to supply heat to a temperature of approximately 650 C. which affords substantially complete reaction of the charge into titanium iodides. Check valves 12 on either. side of the reactor 8 and a globe valve 14 permit isolation of the reactor from the rest of the system during replenishment of the charge.

The mixture of the various titanium iodides produced in the reactor flow to the fractionating column 16 where in only the tetraiodide is permitted to pass through the piping 13 and valves 20 and 22 to the dissociating vacuum furnaces 24. The residual iodides are returned to the reactor 8 by conventional means (not shown). In the arrangement shown,'the dissociation furnac'eto which this invention is particularly directed, is constructed of ceramic or other suitable substantially non-conductive material and is arranged to rotate on bearings 26 concentrically positioned around the tetraiodide inlet 28 and over the liberated iodine outlet 30, and is driven by a conventional motor 32 and gearing arrangement 34. One end of the furnace is appropriately sealed at 26 with a removable end closure 38 to permit removal of the titanium metal product when the furnace is isolated and disconnected from the system by means of valves 2.0 and 21 and adapters 23. Annularly disposed around the furnace 24 is a conventional water cooled induction coil 40, suitably connected to an electric source at 42, to supply the requisite decomposition temperature of approximately 1200 C. in the titanium or other metallic particles which have been introduced into the furnace for the purpose of having titanium deposit thereon.

Completely surrounding the furnace 24 and induction coil 40 is a furnace jacket 44 shown in two equal half portions, a fixed upper half upon which is secured the motor32 and a hinged lower portion suitably closed to the upper half by fasteners 46.

' In order to maintain the wall temperature of the dissociating furnace 24- below that at which titanium will adhere to the wall of the furnace, it may be necessary to supply cooling means in addition to that furnished by that of the water circulating through the induction coils 40. For this purpose apertures 48 are provided in the upper fixed semi-cylindrical half of the jacket 44 to permit exit of cooling air introduced into the annular space 47 through the air inlet valve 43. It will be understood that other means, such as water circulating within the wall of the furnace 24 in any conventional manner may be used to provide the additional wall cooling means.

In order that some means be provided for collecting the titanium metal which is freed during the thermal decomposition of the titanium halide, particles of suitable material, such as titanium or tungsten are introduced into the furnace. Where a rotating furnace is used, bafiles may be used on the wall of the furnace to tumble the particles to assist in the deposition of titanium on the surface of the particles.

When a sufficient amount of titanium metal has deposited on the material introduced for this purpose, the furnace is isolated by closing valves 20 and 21, removing end closures of the jacket and 38 of the furnace, and withdrawing the titanium from the furnace. To place the furnace back into operation the reverse procedure is followed, allowing a sufiicient interim between opening of valves 21 and 20 to permit evacuation and heating of the furnace contents prior to admitting titanium halide. The liberated gaseous halide together with the titanium halide which has not been decomposed is drawn through piping 50 to the condenser 52 wherein the gases are liquitied and returned to reactor 8. To prevent corrosive vapors from being drawn into pumps 2 and 4, conventional cold traps 54 may be interposed in the pipeline leading from the condenser.

In the modified embodiment of the invention which utilizes a dissociating furnace in which the product is continuously discharged, Fig. 2 shows the outlet end of such an inclined rotary furnace and vacuum sealed arrangement for the receptacle into which the furnace outlet leads. The inclined dissociating furnace 69, provided with similar means for heating, cooling, evacuating and driving means as those previously described, may be made longer in length than that of the horizontal type in order to permit a longer period during which titanium can deposit on the surface of particles which are then subsequently discharged intothe outlet 62through the openings 64in the rota r g furnace. Aconventional sealing ring' 66 positioned over the outlet opening 64 prevents access of air into the furnace. In order to prevent air from entering from the outlet receiver 68, a system such as valves 70am 71" maybe utilized to close off the receiver 68. In operation valves 70 are closed and the receiver 68 is evacuated; this may be accomplished by pipe connection between the receiver 68 and the freed iodine vacuum outlet 72. Until the receiver 68 has been cleared of air, titanium accumulates at outlet 62. Valve 70 is then opened and the product permitted to accumulate in the receiver 68. The valve 74) is then closed and the product removed from the receiver 68 through valve 71 which is then closed, the receiver 68 is evacuated, and the outlet cycle repeated as stated.

Of course, it will be understood that although the titanium tetraiodide has been mentioned as the preferred composition to be used in the production of titanium metal, other titanium halides may be employed in the method and apparatus of this invention.

From the foregoing, it is apparent that I have devised a novel method and apparatus embodying the'features and advantages stated in the above description. It is to be understood that the invention is susceptible of various modifications without departing from the spirit or scope of the invention.

What is claimed is:

1. In an apparatus for producing substantially pure titanium metal by the decomposition of titanium halide, a dissociating furnace comprising a sealed, substantially non-electrically conductive chamber, openings in said chamber to permit ingress of gaseous titanium halide and egress of decomposed gaseous halide, an outlet in said chamber'for the removal of the titanium metal, induction heating means positioned outside said chamber, means for cooling the wall of said chamber to a temperature below that at which the titanium halide will decompose and at which titanium metal will adhere to the wall of said chamber, material contained in said chamber upon which titanium metal will deposit, and a jacket mounted around both said chamber and said heating means.

2. In an apparatus for producing substantially pure titanium metal'from the decomposition of titanium halide in an atmosphere substantially free from contaminating gases, a dissociating furnace comprising a sealed substantially non-electrically conductive chamber, openings in said chamber to permit ingress of gaseous titanium halide and egress of the decomposed gaseous halide, an outlet for removal of the titanium metal, induction heating mean positioned outside said chamber, air blast cooling means to maintain the wall of said chamber at a temperature below that at which said titanium freed from decomposition of the halide will adhere to the wall of said chamber, and a jacket around both said chamber and said heating means.

3. In an apparatus for the continuous production of substantially pure titanium metal by decomposing titaniurn halide in av furnace substantially free from contaminating gases; a plurality of dissociating furnaces in parallel relationship, each of said furnaces comprising a substantially electrically non-conductive rotating chamber, removable end closures on said chamber forming a sealed furnace, each of said closures having an opening therein to admit titanium halide and permit evacuation of decomposed gaseous halide, said openings forming bearings on which said chamber rotates, means for rotating said chamber, induction heating means, means for introducing metallic particles into said chamber upon which titanium metal may deposit,'means for cooling the wall of the chamber to a temperature below that at which said titanium will adhere to said wall, and a jacket around both said chamber and said heating means.

4. In an' apparatu for the continuous production of substantially pure titanium metal by thermal decomposition of titanium halide in a furnace substantially free.

from contaminating gases; an inclined rotatably mounted dissociating' furnace' comprising a sealed, substantially 5 electrically non-conductive chamber; openings in said chamber to permit ingress of said titanium halide, and egress of the decomposed gaseous halide, and a discharge outlet permitting removal of the deposited titanium metal; vacuum valve means mounted at said discharge outlet to permit removal of the metal and prevent ingress of contaminating gases through said outlet; induction heating means positioned outside said chamber; cooling means for said chamber wall to maintain the Wall inside said chamber at a temperature below that at which titanium halide will deposit on the Wall of said chamber; means for introducing into said furnace metallic particles which are inductively heated to a temperature at which the titanium halide will be decomposed and upon which the titanium metal may deposit; and a jacket mounted around said chamber and around said heating means.

References Cited in the file of this patent UN'iTED STATES PATENTS 

1. IN AN APPARATUS FOR PRODUCING SUBSTANTIALLY PURE TITANIUM METAL BY THE DECOMPOSITION OF TATANIUM HALIDE, A DISSOCIATING FURNACE COMPRISING A SEALED, SUBSTANTIALLY NON-ELECTRICALLY CONDUCTIVE CHAMBER, OPENINGS IN SAID CHAMBER TO PERMIT INGRESS OF GASEOUS TITANIUM HALIDE AND EGRESS OF DECOMPOSED GASEOUS HALIDE, AN OUTLET IN SAID CHAMBER FOR THE REMOVAL OF THE TITANIUM METAL, INDUCTION HEATING MEANS POSITIONED OUTSIDE SAID CHAMBER, MEANS FOR COOLING THE WALL OF SAID CHAMBER TO A TEMPERATURE BELOW THAT AT WHICH THE TITANIUM HALIDE WILL DECOMPOSE CHAMBER, MATERIAL CONTAINED IN SAID CHAMBER UPON WHICH TITANIUM METAL WILL DEPOSIT, AND A JACKET MOUNTED AROUND BOTH SAID CHAMBER AND SAID HEATING MEANS. 